1. Field of the Invention
This invention relates to a thin-film transistor (TFT). This invention also relates to a method of fabricating a thin-film transistor (TFT).
2. Description of the Prior Art
Liquid crystal displays hold liquid crystal therein and have an array of transparent pixel electrodes for driving pixel-corresponding regions of the liquid crystal. The transparent pixel electrodes are controlled by an array of switching elements generally composed of thin-film transistors (TFT's).
An aperture ratio of a display is an evaluation factor which depends on the ratio of the total area of effective regions of a display screen to the whole area of the display screen. A higher aperture ratio is desirable.
In the liquid crystal display, each of the switching TFT's can be changed between an on state (a conductive state) and an off state (a non-conductive state). A higher internal resistance of the TFT is desirable when the TFT assumes the off state.
ITEJ Technical Report, Vol. 12, No. 50, pp. 7-12, November 1988, discloses a TFT array for a liquid crystal display. As will be explained later, it is generally difficult for the TFT array in the ITEJ documents to simultaneously satisfy both a high aperture ratio and a good TFT off-state characteristic.